Virtually all fabric softener actives in the market place intended for use in liquid dispersions are sold with at least 9% added solvent. For example, Armosoft® DEQ and Arquad® 2HT-75 from Akzo Nobel are 20% and 25%, respectively, of added solvent; the STEPANTEX series and ACCOSOFT series of softener actives from Stepan Co. have 10% added solvent; ADOGEN® 442 and REWOQUAT® WE-18 from Evonik Industries are 25% and 10%, respectively, of added solvent. The conventional thinking is that significant solvent must be added to the fabric softener active to achieve acceptable concentrated aqueous dispersions (F. E. Friedli., et al. J. of Surfactants and Detergents, Vol. 5, No. 3, 2002, page 212) as well as having a product which will have a low enough viscosity in its molten state in order to be moved with conventional pumps while not having to heat it to too high a temperature such that it might decompose. The added solvent is usually a VOC (isopropanol or ethanol) which can ultimately get into the atmosphere and contribute to smog formation. In addition, more fossil fuel needs to be burned in transporting a given amount of fabric softener active than a situation when the amount of added solvent used is reduced or eliminated. If fabric softener actives with reduced or no added solvent can be produced which melt at an acceptable temperature, can easily be pumped while in the molten state, and can be used to make low-viscosity, stable aqueous fabric softener dispersions, there will be economic and environmental benefits.
In U.S. Pat. Nos. 5,637,743 and 5,750,492 (both have the same specification), in spite of the fact that in column 6 the patents state “ . . . a softening composition is obtained which has proved to be directly usable . . . ,” they teach solvent usage in examples 9-15 by demonstrating that a lower cloud temperature than “>80° C.” can be obtained by adding solvent/additive (compound II is referred to as a solvent at the end of Example 8). Indeed, in the examples where aqueous dispersions are made (13-15), in every case the active quat is mixed with 10% isopropanol solvent prior to dispersing in water. It seems the meaning of “directly usable” in column 6 is that no further processing steps are required such as separating out the alkyl glycerides—clearly the patent teaches away from as is usage of the reaction mixture for making the aqueous dispersions as in every example, at least 10% solvent or additive is employed.
In U.S. Patent Publication No. 2006/0089293 compositions which can be directly added to water are described. However, in all 9 examples provided in Example 1, the fabric softener active composition is at least 25% of added solvent.
In U.S. Patent Publication Nos. 2007/0054835 and 2011/0219730, compositions which can be dispersed directly into water are described. However, in the example provided, a diluent is added to the fabric softener active during synthesis in an amount that the fabric softener composition is 10% added diluent—also, during the production of the aqueous dispersion, the aqueous mixture is heated to at least 80° C. in all the examples provided.
In WO 2011/123284, a fabric softener active is disclosed which the application states can be added directly to water in the absence of solvent to create the dispersion. However, the water must be heated to 70° C. which is relatively high and requires considerable energy to achieve. In WO 2011/123733 and WO 2011/120822, the same fabric softener active as in WO 2011/123284 is disclosed, along with the same claim to be able to be directly added to water to create the dispersion, but the temperature at which the water must be held is not disclosed. WO 2011/123606 and WO 2011/120836 also disclose the use of low solvent-containing fabric softener active systems but the only example illustrating the low-solvent fabric softener active composition has a solvent amount of 8% by weight.
In Italian patent application number 2008/1859A, a fabric softening composition is described which does not use solvent. However, it is provided in solid (flake) form which is added directly to water without melting it first and therefore has the drawback of having to use special solid handling equipment for the fabric softener active material.
Thus, there is a need for a fabric softener active system which has reduced or no added solvent. There is also a need that the fabric softener active can flow without having to heat it to very high temperatures. There is also a need that stable, low-viscosity, liquid fabric softener dispersions made from the fabric softener active can be made using standard existing processes known to those skilled in the art.